FDA approves first, oral LHRH antagonist

Earlier today, the US Food and Drug Administration (FDA) approved relugolix, (Orgovyx, from Myovant Sciences), the first, oral luteinizing hormone releasing hormone (LHRH) receptor antagonist for the treatment of adult patients with advanced prostate cancer. Full information about the approval of relugolix is available in this FDA media release. LHRH receptor agonists are also referred to as gonadotropin-releasing hormone (GnRH) receptor antagonists.

The efficacy and safety of relogulix was evaluated in the HERO trial (NCT03085095). This was a randomized, open label trial in men requiring at least 1 year of androgen deprivation therapy (ADT) who had either prostate cancer recurrence following radiation or surgery or newly diagnosed castration-sensitive advanced prostate cancer. A total of 934 patients were randomized (2:1) to receive relugolix (using a 360 mg oral loading dose on the first day, followed by daily oral doses of 120 mg),or leuprolide acetate (using a 22.5 mg injection subcutaneously every 3 months) for 48 weeks.

The main efficacy outcome measure was the achievement and maintenance of a castrate level of serum testosterone (< 50 ng/dl) by day 29 through 48 weeks of treatment. The medical castration rate was 96.7 percent in the relugolix arm of the trial.

The most common adverse reactions (occurring in > 10 percent of patients receiving relugolix) in the HERO trial were: hot flushes, musculoskeletal pain, fatigue, diarrhea, and constipation. The most common laboratory abnormalities (occurring in ≥15 percent of patients receiving relugolix) were increased glucose, triglycerides, alanine aminotransferase, and aspartate aminotransferase. Decreased hemoglobin was also observed.

The recommended relugolix dose is a loading dose of 360 mg on the first day followed by a daily oral dose of 120 mg at approximately the same time with or without food. Because it is an LHRH antagonist, relugolix does not have to be given with an initial short course of an antiandrogen like bicalutamide.

For those who are interested, the full, detailed prescribing information for physicians can be found here on the FDA web site. Myovant Sciences has yet to issue their own press release as of 1:30 p.m. Eastern today.

6 Responses

  1. I’ve been checking the Myovant website for info on how much of a supply they have and how long distribution will take. Because of the Lupron shortage, many men are ready for it now.

  2. Would like to know how the cost compares to Lupron. Oral drugs on pharmacy co-pays are cheaper than in office administered drugs like Lupron.

  3. Sorry … Don’t know the answer to that question yet.

  4. Interested to discover additional time to survival benefit, as opposed to risks of adverse reaction to treatment, and whether it makes sense on an individual personal basis .

  5. Dandy:

    As yet there is no information about the long-term use of this new form of LHRH antagonist (i.e., > 12 months) or whether it has any survival benefit compared to the injectable forms of LHRH agonists and LHRH antagonists. However, it seems unlikely that there would be any difference in the survival benefit.

    If you look at the product prescribing information, based on the data from the clinical trial (see Sec. 6, Table 1), you will see that the most common side effects of relugolix were almost identical to those of leuprolide acetate.

  6. Sometimes it takes a while for a drug manufacturer to ramp up production and get it into wide distribution, but Myovant is predicting Orgovyx (relugolix) will be available next month, according to the new product website. An internet site says Orgovyx carries a list price of $2,313 per bottle containing 30 pills (ouch!). No info on which drug plans will cover it, but there is a cost-assistance program, and there is a 2-month free trial:

    There is a known side effect on the electrical activity of the heart. Here is a link the full prescribing info.

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